In the prior art, various wedge retention systems have been devised for securing an indexable insert within an insert pocket of a cutting tool. The cutting tool, which for example, may be of the type which is intended to be rotated about a central axis, is provided with at least one insert pocket which is adapted to receive an indexable cutting insert having opposed planar rake surfaces and a plurality of sharpened edge faces. The insert pocket has opposed generally planar leading and trailing walls. In use, an insert is mounted in the pocket and is secured therein by a wedge. Preferably, the wedge is readily removable to allow the indexing of the insert when the exposed cutting edge becomes worn.
In a cutting operation, relatively strong forces are exerted on the cutting edges of the insert. In order to prevent the insert from shifting within the insert pocket, the cutting tool is designed such that the wedge securely presses the insert against a wall of the pocket, at a point of the insert adjacent the upper edge of a rake face. While this arrangement functions to maintain the insert within the pocket, localized stresses arise at the points of contact which tend to cause the inserts to crack or fracture. Further, after a period of use, an insert may shift into an out of parallel orientation which will also cause localized stresses to develop.
The problems associated with the occurrence of localized stresses became more acute when ceramic inserts are utilized instead of the more common hardened tungsten carbide inserts. Ceramic inserts, while advantageous in certain operations, such as the milling of cast iron parts in the auto industry, tend to be relatively brittle and will fracture easily if subjected to localized stresses.
To reduce the likelihood of fracture of the ceramic inserts, the insert pockets of the cutting tool must be accurately machined to precise gauge tolerances such that full and equal contact pressure is established between the pocket wall and the insert, thereby reducing localized stresses. As can be appreciated, the machining of insert pockets to fine tolerances is time consuming and expensive. Further, even when the pockets are properly machined, the inserts may still shift to an out of parallel orientation wherein localized stresses will develop.
Accordingly, it is an object of the subject invention to provide a new and improved floating wedge which enables full and equal contact pressure to be established between the walls of the insert pocket and the insert, thereby eliminating localized stresses which will result in insert fracture.
It is another object of the subject invention to provide a floating wedge which will inhibit the development of localized stresses and eliminate the necessity of machining an insert pocket to highly accurate gauge tolerances.
It is a further object of the subject invention to provide a floating wedge consisting of a main body member and a swivel plate member which are capable of relative movement such that the orientation of the leading surface of the wedge relative to the trailing surface of the wedge may be adjusted, to facilitate the alignment of the insert within the insert pocket.
It is still another object of the subject invention to provide a wedge assembly wherein both the axial and radial float may be adjusted when mounting an insert in a cutting tool.